On Friday, August 8, 2003, at 13:26, Robert G Palmer Jr wrote: Pardon my post if this is not the appropriate list - I looked at darwin-userlevel and it seemed too general. If this isn't the appropriate place, please let me know. I'm working on my cocoa application, which does some network communication. I am using sockets with the sin_addr portion of the sockaddr_in set to INADDR_BROADCAST. I have run into a problem and need some help. I need to send a general network broadcast (IP = 255.255.255.255), but under BSD implementations of sockets, if I specify the general broadcast address, the sockets layer automatically masks it to the interface's subnet, thus creating a subnet broadcast (e.g. if the subnet mask is 255.255.255.0 and my IP is 192.168.20.73, then the broadcast would be 192.168.20.255). I MUST have a full general broadcast. Steven's book says that BSD v3.0 includes a new flag IP_ONESBROADCAST (pg 471) that will do this, but I can't find any reference to this in the OS X headers or documentation (or man pages). Does anyone know how to get OS X to send a general broadcast instead of a subnet broadcast? If you can use a link-local multicast instead of fighting the system to send an all ones broadcast, you'll probably end up much happier. The multicast APIs let you specify which interface a packet should be sent on. You'll have no way of doing this with the broadcast packet, so you can only broadcast on one interface. I think there is a way to send the all ones multicast, but I don't recall what it is. I think it does require root privileges. -josh _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.